/* SSE2 version of strlen.
- Copyright (C) 2012-2015 Free Software Foundation, Inc.
+ Copyright (C) 2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
#include <sysdep.h>
-/* Long lived register in strlen(s), strnlen(s, n) are:
-
- %xmm11 - zero
- %rdi - s
- %r10 (s+n) & (~(64-1))
- %r11 s+n
-*/
.text
ENTRY(strlen)
-
-/* Test 64 bytes from %rax for zero. Save result as bitmask in %rdx. */
-#define FIND_ZERO \
- pcmpeqb (%rax), %xmm8; \
- pcmpeqb 16(%rax), %xmm9; \
- pcmpeqb 32(%rax), %xmm10; \
- pcmpeqb 48(%rax), %xmm11; \
- pmovmskb %xmm8, %esi; \
- pmovmskb %xmm9, %edx; \
- pmovmskb %xmm10, %r8d; \
- pmovmskb %xmm11, %ecx; \
- salq $16, %rdx; \
- salq $16, %rcx; \
- orq %rsi, %rdx; \
- orq %r8, %rcx; \
- salq $32, %rcx; \
- orq %rcx, %rdx;
-
#ifdef AS_STRNLEN
-/* Do not read anything when n==0. */
+ mov %rsi, %r8
+ xor %edx, %edx
test %rsi, %rsi
- jne L(n_nonzero)
- xor %rax, %rax
- ret
-L(n_nonzero):
-
-/* Initialize long lived registers. */
-
- add %rdi, %rsi
- mov %rsi, %r10
- and $-64, %r10
- mov %rsi, %r11
+ je L(return_zero)
+ cmp $64, %rsi
+ jae L(dont_set)
+ bts %rsi, %rdx
+L(dont_set):
#endif
-
- pxor %xmm8, %xmm8
- pxor %xmm9, %xmm9
- pxor %xmm10, %xmm10
- pxor %xmm11, %xmm11
- movq %rdi, %rax
- movq %rdi, %rcx
- andq $4095, %rcx
-/* Offsets 4032-4047 will be aligned into 4032 thus fit into page. */
- cmpq $4047, %rcx
-/* We cannot unify this branching as it would be ~6 cycles slower. */
+ pxor %xmm0, %xmm0
+ mov %edi, %ecx
+ and $4095, %ecx
+ cmp $4032, %ecx
ja L(cross_page)
-
+ movdqu (%rdi), %xmm4
+ pcmpeqb %xmm0, %xmm4
+ pmovmskb %xmm4, %ecx
#ifdef AS_STRNLEN
-/* Test if end is among first 64 bytes. */
-# define STRNLEN_PROLOG \
- mov %r11, %rsi; \
- subq %rax, %rsi; \
- andq $-64, %rax; \
- testq $-64, %rsi; \
- je L(strnlen_ret)
+ or %dx, %cx
#else
-# define STRNLEN_PROLOG andq $-64, %rax;
+ test %ecx, %ecx
#endif
-
-/* Ignore bits in mask that come before start of string. */
-#define PROLOG(lab) \
- movq %rdi, %rcx; \
- xorq %rax, %rcx; \
- STRNLEN_PROLOG; \
- sarq %cl, %rdx; \
- test %rdx, %rdx; \
- je L(lab); \
- bsfq %rdx, %rax; \
+ je L(next48_bytes)
+ bsf %ecx, %eax
ret
#ifdef AS_STRNLEN
- andq $-16, %rax
- FIND_ZERO
-#else
- /* Test first 16 bytes unaligned. */
- movdqu (%rax), %xmm12
- pcmpeqb %xmm8, %xmm12
- pmovmskb %xmm12, %edx
- test %edx, %edx
- je L(next48_bytes)
- bsf %edx, %eax /* If eax is zeroed 16bit bsf can be used. */
+L(return_zero):
+ xor %eax, %eax
ret
-
+L(return_noread):
+ add $64, %rax
+ sub %rdi, %rax
+ ret
+#endif
+ .p2align 4
L(next48_bytes):
-/* Same as FIND_ZERO except we do not check first 16 bytes. */
- andq $-16, %rax
- pcmpeqb 16(%rax), %xmm9
- pcmpeqb 32(%rax), %xmm10
- pcmpeqb 48(%rax), %xmm11
- pmovmskb %xmm9, %edx
- pmovmskb %xmm10, %r8d
- pmovmskb %xmm11, %ecx
- salq $16, %rdx
- salq $16, %rcx
- orq %r8, %rcx
+ movdqu 16(%rdi), %xmm1
+ movdqu 32(%rdi), %xmm2
+ movdqu 48(%rdi), %xmm3
+ pcmpeqb %xmm0, %xmm1
+ pcmpeqb %xmm0, %xmm2
+ pcmpeqb %xmm0, %xmm3
+#ifdef AS_STRNLEN
+ pmovmskb %xmm1, %ecx
+ sal $16, %ecx
+ or %rcx, %rdx
+#else
+ pmovmskb %xmm1, %edx
+ sal $16, %edx
+#endif
+ pmovmskb %xmm2, %esi
+ pmovmskb %xmm3, %ecx
+ sal $16, %ecx
+ or %esi, %ecx
salq $32, %rcx
orq %rcx, %rdx
-#endif
-
- /* When no zero byte is found xmm9-11 are zero so we do not have to
- zero them. */
- PROLOG(loop)
+ je L(loop_init)
+ bsfq %rdx, %rax
+ ret
.p2align 4
L(cross_page):
- andq $-64, %rax
- FIND_ZERO
- PROLOG(loop_init)
+ movq %rdi, %rax
+ pxor %xmm1, %xmm1
+ pxor %xmm2, %xmm2
+ pxor %xmm3, %xmm3
#ifdef AS_STRNLEN
-/* We must do this check to correctly handle strnlen (s, -1). */
-L(strnlen_ret):
- bts %rsi, %rdx
+ mov %rdx, %r9
+#endif
+ andq $-64, %rax
+ pcmpeqb (%rax), %xmm0
+ pcmpeqb 16(%rax), %xmm1
+ pcmpeqb 32(%rax), %xmm2
+ pcmpeqb 48(%rax), %xmm3
+ pmovmskb %xmm0, %esi
+ pxor %xmm0, %xmm0
+ pmovmskb %xmm1, %edx
+ pmovmskb %xmm2, %r10d
+ pmovmskb %xmm3, %ecx
+ sal $16, %edx
+ sal $16, %ecx
+ or %esi, %edx
+ or %r10, %rcx
+ salq $32, %rcx
+ orq %rcx, %rdx
+ mov %edi, %ecx
+#ifdef AS_STRNLEN
+ salq %cl, %r9
+ or %r9, %rdx
+#endif
sarq %cl, %rdx
test %rdx, %rdx
je L(loop_init)
bsfq %rdx, %rax
ret
-#endif
.p2align 4
L(loop_init):
- pxor %xmm9, %xmm9
- pxor %xmm10, %xmm10
- pxor %xmm11, %xmm11
+ movq %rdi, %rax
+ andq $-64, %rax
#ifdef AS_STRNLEN
+ add %rdi, %r8
+ sub %rax, %r8
+ cmp $64, %r8
+ je L(return_noread)
+#endif
+ pxor %xmm1, %xmm1
+ pxor %xmm2, %xmm2
+#ifdef USE_AVX2
+ vpxor %xmm0, %xmm0, %xmm0
+#endif
.p2align 4
L(loop):
+#ifdef USE_AVX2
+ vmovdqa 64(%rax), %ymm1
+ vpminub 96(%rax), %ymm1, %ymm2
+ vpcmpeqb %ymm0, %ymm2, %ymm2
+ vpmovmskb %ymm2, %edx
+#else
+ movdqa 64(%rax), %xmm5
+ pminub 80(%rax), %xmm5
+ pminub 96(%rax), %xmm5
+ pminub 112(%rax), %xmm5
+ pcmpeqb %xmm0, %xmm5
+ pmovmskb %xmm5, %edx
+#endif
- addq $64, %rax
- cmpq %rax, %r10
- je L(exit_end)
-
- movdqa (%rax), %xmm8
- pminub 16(%rax), %xmm8
- pminub 32(%rax), %xmm8
- pminub 48(%rax), %xmm8
- pcmpeqb %xmm11, %xmm8
- pmovmskb %xmm8, %edx
+#ifdef AS_STRNLEN
+ sub $64, %r8
testl %edx, %edx
- jne L(exit)
- jmp L(loop)
-
- .p2align 4
-L(exit_end):
- cmp %rax, %r11
- je L(first) /* Do not read when end is at page boundary. */
- pxor %xmm8, %xmm8
- FIND_ZERO
-
-L(first):
- bts %r11, %rdx
- bsfq %rdx, %rdx
- addq %rdx, %rax
- subq %rdi, %rax
- ret
-
- .p2align 4
-L(exit):
- pxor %xmm8, %xmm8
- FIND_ZERO
-
- bsfq %rdx, %rdx
- addq %rdx, %rax
- subq %rdi, %rax
- ret
-
+ jne L(exit64)
+ cmp $64, %r8
+ jbe L(exit64_zero)
#else
-
- /* Main loop. Unrolled twice to improve L2 cache performance on core2. */
- .p2align 4
-L(loop):
-
- movdqa 64(%rax), %xmm8
- pminub 80(%rax), %xmm8
- pminub 96(%rax), %xmm8
- pminub 112(%rax), %xmm8
- pcmpeqb %xmm11, %xmm8
- pmovmskb %xmm8, %edx
testl %edx, %edx
jne L(exit64)
+#endif
subq $-128, %rax
-
- movdqa (%rax), %xmm8
- pminub 16(%rax), %xmm8
- pminub 32(%rax), %xmm8
- pminub 48(%rax), %xmm8
- pcmpeqb %xmm11, %xmm8
- pmovmskb %xmm8, %edx
+#ifdef USE_AVX2
+ vmovdqa (%rax), %ymm1
+ vpminub 32(%rax), %ymm1, %ymm2
+ vpcmpeqb %ymm0, %ymm2, %ymm2
+ vpmovmskb %ymm2, %edx
+#else
+ movdqa (%rax), %xmm5
+ pminub 16(%rax), %xmm5
+ pminub 32(%rax), %xmm5
+ pminub 48(%rax), %xmm5
+ pcmpeqb %xmm0, %xmm5
+ pmovmskb %xmm5, %edx
+#endif
+#ifdef AS_STRNLEN
+ sub $64, %r8
testl %edx, %edx
jne L(exit0)
+ cmp $64, %r8
+ jbe L(exit0_zero)
+#else
+ testl %edx, %edx
+ jne L(exit0)
+#endif
jmp L(loop)
+#ifdef AS_STRNLEN
+ .p2align 4
+L(exit64_zero):
+ addq $64, %rax
+L(exit0_zero):
+ add %r8, %rax
+ sub %rdi, %rax
+ ret
+#endif
.p2align 4
+
+
L(exit64):
addq $64, %rax
L(exit0):
- pxor %xmm8, %xmm8
- FIND_ZERO
-
+#ifdef USE_AVX2
+ sal $32, %rdx
+#else
+ sal $48, %rdx
+#endif
+#ifdef AS_STRNLEN
+ cmp $64, %r8
+ jae L(dont_set2)
+ bts %r8, %rdx
+ L(dont_set2):
+#endif
+#ifdef USE_AVX2
+ subq %rdi, %rax
+ vpcmpeqb %ymm0, %ymm1, %ymm1
+ vpmovmskb %ymm1, %ecx
+ vzeroupper
+ or %rcx, %rdx
+#else
+ pcmpeqb (%rax), %xmm0
+ pcmpeqb 16(%rax), %xmm1
+ pcmpeqb 32(%rax), %xmm2
+ subq %rdi, %rax
+ pmovmskb %xmm0, %esi
+ pmovmskb %xmm1, %ecx
+ pmovmskb %xmm2, %r8d
+ sal $16, %ecx
+ or %esi, %ecx
+ salq $32, %r8
+ orq %r8, %rcx
+ orq %rcx, %rdx
+#endif
bsfq %rdx, %rdx
addq %rdx, %rax
- subq %rdi, %rax
ret
-
-#endif
-
END(strlen)
libc_hidden_builtin_def (strlen)
projects / thirdparty / glibc.git / commitdiff
